PHOENIX - Thieves struck a daycare center that serves children with special needs in the Phoenix area, removing copper valves from the outside of the building.

United Cerebral Palsy of Central Arizona spent $6,600 to repair the damage, the Arizona Republic reported. The center closed down for a day because the missing valves had allowed fresh water into the building.

Thefts of copper have become increasingly common because of high commodity prices. But parents of children who get daycare or therapy at the UCP center said the theft was especially low.

"It's like stealing wheelchairs from an old-folks home," said Matt Patterson.

The building was hit during the weekend. The thieves used a saw to remove two 80-pound valves and one 40-pounder.